Clean little engine. So many of these trucks have changed hands that typically someone has started ripping stuff off, and then they wonder why it doesn't run right.What he said. Connects to the aircleaner to provide heated air off the exhaust to warm the engine up faster. When cold, engine vacuum open a flapper that allows the warm air off the exhaust to flow into the aircleaner. As the engine warms up (so does the bypass valve) it shuts off the vacuum and the flapper closes.
Since it's part of the emissions system, I failed smog test one year only because that tube was missing. I was able to replace it with some flex tubing from a nearby Volkswagen speed shop (the old Beetles used these).
You didn't saw what year/model/engine you have so here's my D21 2.4. The red lines indicate where the hot air tube would be (wasn't there when I took this pic). The gizmo in green is the bypass.
View attachment 10123
I'm confused...please help me understand what you're saying
It's just a way for the engine to tell when it's getting warm, so the "auto choke" feature turns off. I put "auto choke" in quotes because the engine doesn't really have a choke.what is the name of the tube coming off the exhaust manifold? I need to replace it but don't know what it's called. It's not the EGR tube that goes across the engine to the EGR valve, I talking about the other tube on the outside